醇羟基对碳酸钙矿物成核物相及界面能影响研究

Effect of Hydroxyl Group on Nucleation of Calcium Carbonate Phases in Alcohol-Water Mixtures

文章通过对醇类物质参与下的碳酸钙成核过程进行研究,探讨生物流体中常见的羟基对矿物物相以及界面能的影响。研究结果表明多羟基醇有利于亚稳定球文石的形成,醇的加入会增加方解石和球文石的界面能,醇的羟基定向吸附造成的吸附位密度降低是提升矿物界面能最可能的机制,而溶剂氢键数量决定了碳酸根的自由度,有利于对称度低且CO2-3不平行的球文石形成。水和乙醇—水体系氢键作用弱,界面能低的方解石物相成为热力学优势物相。研究结果凸显了生物成矿流体受羟基影响强烈,通过控制流体中羟基物质含量,生物体可以完全掌控碳酸钙物相的形成部位,加深了对生物成因碳酸钙形成过程的理解。

In this paper,the effect of hydroxyl groups on CaCO3 mineral phases and their interfacial energies in biological-like fluids(alcohol-water mixtures)were studied.The results show that polyhydroxy alcohols are beneficial to the formation of metastable vaterite,and the addition of alcohols can increase the interfacial energies between calcite and vaerite.The decrease of total absoption site density due to the hydroxyl-oriented adsorption of alcohols is most likely the mechanism to increase the mineral interface,and the number of hydrogen bonds in solvents determines the degree of freedom of carbonate ions resulting in the formation of vaterite,whose CO2-3 plane is nonparallel.In solvents with weak hydrogen net work,the calcite phase is the thermodynamic-favouriable phase due to the low interfacial energy between water and ethanol-water.The results show that the bio-mineralizing fluid can strongly affect the carbontion process through hydroxyl function group.By controlling the content of hydroxyl group in the fluid,the living organisms can select the formation site of calcium carbonate phase,which extends our understanding about the origine of stable biogenic calcium carbonates.